Improved photovoltaic characteristics of amorphous Si thin-film solar cells containing nanostructure silver conductors fabricated using a non-vacuum process

A low-cost, highly reflective, liquid organic nanostructure silver conductor with superior conductivity, using back contact reflectors in amorphous silicon (a-Si) single-junction superstrate configuration thin-film solar cells produced using a non-vacuum screen printing process is proposed. The conductive paste is composed of Ag nanowires (Ag NWs) mixed with an Ag nanostructure (Ag NS) sheet. The paste is referred to as ‘Ag NWS’. A comparison of silver conductor samples with vacuum-system-sputtered silver samples indicated that the short-circuit current density (J sc) and the open-circuit voltage (V oc) of Ag NWS conductor cells exceeded 0.22 mA/cm2 and 66 mV, respectively. The Ag NWS conductor with back contact reflectors in solar cells was analysed using external quantum efficiency measurements to effectively enhance light-trapping ability in a long wavelength region (580–700 nm). The cells constructed using the optimised Ag NWS demonstrated an increase of approximately 6.1% in power conversion efficiency under AM 1.5 illumination. These results indicated that the Ag NWS conductor back contact reflector layer is a suitable candidate for high-performance a-Si thin-film solar cells.